CN103175381A - Process for preparing LNG (liquefied natural gas) by low-concentration coal bed gas oxygen-containing cryogenic liquefaction - Google Patents
Process for preparing LNG (liquefied natural gas) by low-concentration coal bed gas oxygen-containing cryogenic liquefaction Download PDFInfo
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- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 title claims description 56
- 239000001301 oxygen Substances 0.000 title claims description 56
- 229910052760 oxygen Inorganic materials 0.000 title claims description 56
- 239000007789 gas Substances 0.000 title claims description 53
- 239000003949 liquefied natural gas Substances 0.000 title claims description 40
- 239000003245 coal Substances 0.000 title claims description 11
- 238000004519 manufacturing process Methods 0.000 title description 8
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims abstract description 184
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 claims abstract description 120
- 229910052757 nitrogen Inorganic materials 0.000 claims abstract description 91
- 238000000034 method Methods 0.000 claims abstract description 74
- 238000001816 cooling Methods 0.000 claims abstract description 27
- 238000005057 refrigeration Methods 0.000 claims abstract description 22
- QWTDNUCVQCZILF-UHFFFAOYSA-N isopentane Chemical compound CCC(C)C QWTDNUCVQCZILF-UHFFFAOYSA-N 0.000 claims abstract description 16
- 238000007906 compression Methods 0.000 claims abstract description 12
- 230000006835 compression Effects 0.000 claims abstract description 12
- 238000000746 purification Methods 0.000 claims abstract description 12
- AFABGHUZZDYHJO-UHFFFAOYSA-N dimethyl butane Natural products CCCC(C)C AFABGHUZZDYHJO-UHFFFAOYSA-N 0.000 claims abstract description 8
- 238000000926 separation method Methods 0.000 claims abstract description 5
- 239000012071 phase Substances 0.000 claims description 34
- 239000007788 liquid Substances 0.000 claims description 12
- 239000004215 Carbon black (E152) Substances 0.000 claims description 10
- 229930195733 hydrocarbon Natural products 0.000 claims description 10
- 150000002430 hydrocarbons Chemical class 0.000 claims description 10
- 239000007791 liquid phase Substances 0.000 claims description 9
- 239000000203 mixture Substances 0.000 claims description 9
- ATUOYWHBWRKTHZ-UHFFFAOYSA-N Propane Chemical compound CCC ATUOYWHBWRKTHZ-UHFFFAOYSA-N 0.000 claims description 6
- DOTMOQHOJINYBL-UHFFFAOYSA-N molecular nitrogen;molecular oxygen Chemical compound N#N.O=O DOTMOQHOJINYBL-UHFFFAOYSA-N 0.000 claims description 6
- 238000010992 reflux Methods 0.000 claims description 5
- 238000010438 heat treatment Methods 0.000 claims description 4
- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 claims description 3
- 239000001294 propane Substances 0.000 claims description 3
- 230000008929 regeneration Effects 0.000 claims description 3
- 238000011069 regeneration method Methods 0.000 claims description 3
- 238000003860 storage Methods 0.000 claims description 3
- 238000004140 cleaning Methods 0.000 claims 3
- 239000003507 refrigerant Substances 0.000 abstract description 118
- 239000003345 natural gas Substances 0.000 abstract description 17
- 238000004064 recycling Methods 0.000 abstract description 12
- NLOAOXIUYAGBGO-UHFFFAOYSA-N C.[O] Chemical compound C.[O] NLOAOXIUYAGBGO-UHFFFAOYSA-N 0.000 abstract description 10
- NNPPMTNAJDCUHE-UHFFFAOYSA-N isobutane Chemical compound CC(C)C NNPPMTNAJDCUHE-UHFFFAOYSA-N 0.000 abstract description 10
- 238000009833 condensation Methods 0.000 abstract description 7
- 230000005494 condensation Effects 0.000 abstract description 7
- 238000001704 evaporation Methods 0.000 abstract description 6
- 230000008020 evaporation Effects 0.000 abstract description 6
- 239000001282 iso-butane Substances 0.000 abstract description 5
- 238000005516 engineering process Methods 0.000 abstract description 3
- 239000000047 product Substances 0.000 description 10
- 239000002994 raw material Substances 0.000 description 4
- 239000002826 coolant Substances 0.000 description 3
- MYMOFIZGZYHOMD-UHFFFAOYSA-N Dioxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 description 2
- 239000005977 Ethylene Substances 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 229910001873 dinitrogen Inorganic materials 0.000 description 2
- 229910001882 dioxygen Inorganic materials 0.000 description 2
- 238000004821 distillation Methods 0.000 description 2
- 238000005065 mining Methods 0.000 description 2
- QJGQUHMNIGDVPM-UHFFFAOYSA-N nitrogen(.) Chemical compound [N] QJGQUHMNIGDVPM-UHFFFAOYSA-N 0.000 description 2
- 238000007711 solidification Methods 0.000 description 2
- 230000008023 solidification Effects 0.000 description 2
- 239000002699 waste material Substances 0.000 description 2
- 239000006227 byproduct Substances 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 238000002485 combustion reaction Methods 0.000 description 1
- 230000018109 developmental process Effects 0.000 description 1
- 238000004880 explosion Methods 0.000 description 1
- 238000000605 extraction Methods 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 238000003303 reheating Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000009834 vaporization Methods 0.000 description 1
- 230000008016 vaporization Effects 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
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Abstract
本发明公开了一种低浓度煤层气含氧深冷液化制取LNG工艺，包括：1）压缩净化工序；2）液化分离工序：包括：a．主流程工艺；b．制冷工艺：包括：b1．混合冷剂工艺；b2．氮冷剂工艺：氮冷剂经压缩、冷却后依次通过一级换热器、二级换热器、三级换热器和过冷器冷却降温，将节流后的氮冷剂进入塔顶冷凝器输出冷量，然后将气态的氮冷剂依次通过过冷器、三级换热器、二级换热器、一级换热器逐级升温至常温后回流至氮压缩机循环利用。通过混合冷剂工艺控制塔底蒸发量，通过氮冷剂工艺控制塔顶冷凝量，能够独立调整天然气产品的纯度和收率，而且低温区的冷剂仅有氮组分，不存在异丁烷、异戊烷等重组分，从而解决节流不制冷，或冷剂通道堵塞问题。
The invention discloses a low-concentration coalbed methane oxygen-containing cryogenic liquefaction process for producing LNG, including: 1) compression and purification process; 2) liquefaction separation process: including: a. Main process technology; b. Refrigeration process: including: b1 . Mixed refrigerant process; b 2 . Nitrogen refrigerant process: After compression and cooling, the nitrogen refrigerant passes through the primary heat exchanger, secondary heat exchanger, tertiary heat exchanger and subcooler to cool down in turn, and the throttled nitrogen refrigerant enters the top of the tower The condenser outputs the cooling capacity, and then the gaseous nitrogen refrigerant passes through the subcooler, the third-stage heat exchanger, the second-stage heat exchanger, and the first-stage heat exchanger to raise the temperature step by step to normal temperature, and then returns to the nitrogen compressor for recycling. The evaporation at the bottom of the tower is controlled by the mixed refrigerant process, and the condensation at the top of the tower is controlled by the nitrogen refrigerant process, which can independently adjust the purity and yield of natural gas products, and the refrigerant in the low temperature zone is only nitrogen components, and there is no isobutane , Isopentane and other heavy components, so as to solve the problem of throttling without refrigeration or blockage of refrigerant channels.
Description
技术领域 technical field
本发明属于通过加压和冷却处理使气体或气体混合物进行液化、固化或分离的技术领域，具体的为一种低浓度煤层气含氧深冷液化制取LNG工艺。 The invention belongs to the technical field of liquefaction, solidification or separation of gas or gas mixture through pressurization and cooling treatment, and specifically relates to a process for producing LNG by cryogenic liquefaction of low-concentration coal bed gas containing oxygen.
背景技术 Background technique
含氧煤层气是煤矿在开采过程中为防止瓦斯爆炸和突出，保证煤矿安全生产而抽排出的初级副产品，其主要成分为甲烷，从其成分含量上可以看出，煤层气是较为重要的能源和化工原料。但是由于其成分较为复杂，特别是在煤层气中含有氧，是非常危险的助燃助爆剂，制约了含氧煤层气的综合利用，实践中，为了节约成本，煤层气普遍在采煤过程中排入大气，造成资源的极度浪费和对环境造成污染。 Oxygen-containing coalbed methane is the primary by-product pumped out during coal mining to prevent gas explosions and outbursts and ensure safe production in coal mines. Its main component is methane. From its composition content, it can be seen that coalbed methane is an important energy source. and chemical raw materials. However, due to its complex composition, especially the oxygen contained in coalbed methane, it is a very dangerous combustion and explosion-supporting agent, which restricts the comprehensive utilization of oxygen-containing coalbed methane. In practice, in order to save costs, coalbed methane is generally used in the coal mining process. Exhausted into the atmosphere, causing extreme waste of resources and pollution to the environment.
随着技术的发展，目前在低浓度煤层气提纯制取天然气的领域中，出现了多种含氧煤层气的液化技术。公开号为CN101922850A和CN101929788A分别公开了一种利用含氧煤层气制取液化天然气的方法和利用含氧煤层气制取液化天然气的装置，该方法和装置采用混合冷剂自复叠制冷循环，将净化后的原料气液化并分离，得到LNG产品，该方法和装置虽然能够利用含氧煤层气制取天然气，但是还存在以下问题： With the development of technology, various liquefaction technologies of oxygen-containing coalbed methane have emerged in the field of purification of low-concentration coalbed methane to produce natural gas. Publication Nos. CN101922850A and CN101929788A respectively disclose a method for producing liquefied natural gas from oxygen-containing coalbed methane and a device for producing liquefied natural gas from oxygen-containing coalbed methane. The method and device use a mixed refrigerant self-cascading refrigeration cycle. The purified raw gas is liquefied and separated to obtain LNG products. Although this method and device can use oxygen-containing coalbed methane to produce natural gas, there are still the following problems:
（1）原料气（即低浓度煤层气）来自于煤矿井下抽采，甲烷含量波动较大，难免会影响液化工艺的稳定运行，需要对装置进行调整；而该方法和装置中天然气产品的纯度和收率分别由塔底蒸发量和塔顶冷凝量控制，但为塔底加热和为塔顶冷却的制冷剂流体为同一股，因此在调整产品纯度时会影响塔顶冷凝量（收率），同样，调整产品收率时又会影响到塔底蒸发量（纯度）； (1) The raw material gas (i.e. low-concentration coalbed methane) comes from the underground extraction of coal mines, and the methane content fluctuates greatly, which will inevitably affect the stable operation of the liquefaction process, and the device needs to be adjusted; and the purity of the natural gas product in the method and device And the yield is controlled by the evaporation at the bottom of the tower and the condensation at the top of the tower, but the refrigerant fluid for heating the bottom of the tower and cooling for the top of the tower is the same, so when adjusting the product purity, it will affect the condensation at the top of the tower (yield) , similarly, when adjusting the product yield, it will affect the bottom evaporation (purity);
（2）如果冷剂压缩机工况不稳定，会导致大量混合冷剂中的重组分（如异丁烷、异戊烷）进入液化装置的低温区（温度低于－165℃），造成该段冷剂温度低于其下转化温度，使节流后温度升高（即不制冷），严重时亦会导致凝固，使冷剂通道堵塞； (2) If the working condition of the refrigerant compressor is unstable, a large amount of heavy components (such as isobutane and isopentane) in the mixed refrigerant will enter the low temperature area of the liquefaction device (the temperature is lower than -165°C), causing the The temperature of the refrigerant in the first stage is lower than its lower conversion temperature, so that the temperature rises after throttling (that is, no cooling), and in severe cases, it will also cause solidification and block the refrigerant channel;
（3）煤层气中甲烷被提出后，氮氧尾气在精馏塔的操作压力（0.3MPa）下直接复热排空，未充分回收其能量（压力能），浪费能源。 (3) After the methane in the coalbed methane is extracted, the nitrogen and oxygen tail gas is directly reheated and emptied under the operating pressure (0.3MPa) of the rectification tower, and its energy (pressure energy) is not fully recovered, which is a waste of energy.
有鉴于此，本发明旨在探索一种低浓度煤层气含氧深冷液化制取LNG工艺，该低浓度煤层气含氧深冷液化制取LNG工艺不仅能够独立调整天然气产品的纯度和收率，而且能够防止冷剂通道堵塞，并提高提高能源利用。 In view of this, the present invention aims to explore a low-concentration coalbed methane oxygen-containing cryogenic liquefaction process for producing LNG, which can not only independently adjust the purity and yield of natural gas products , and can prevent the blockage of the refrigerant channel, and improve energy utilization.
发明内容 Contents of the invention
本发明的目的在于提供一种低浓度煤层气含氧深冷液化制取LNG工艺，该低浓度煤层气含氧深冷液化制取LNG工艺不仅能够独立调整天然气产品的纯度和收率，而且能够防止冷剂通道堵塞。 The purpose of the present invention is to provide a low-concentration coalbed methane oxygen-containing cryogenic liquefaction process for producing LNG. The low-concentration coalbed methane oxygen-containing cryogenic liquefaction process can not only independently adjust the purity and yield of natural gas products, but also can Prevent the refrigerant channel from being clogged.
为实现上述技术目的，本发明提供如下技术方案： In order to achieve the above technical purpose, the present invention provides the following technical solutions:
一种低浓度煤层气含氧深冷液化制取LNG工艺，包括： A low-concentration coalbed methane oxygen-containing cryogenic liquefaction process to produce LNG, including:
1）压缩净化工序：将低浓度含氧煤层原料气经压缩净化后得到净化含氧煤层气； 1) Compression and purification process: the low-concentration oxygen-containing coal bed raw material gas is compressed and purified to obtain purified oxygen-containing coal bed methane;
2）液化分离工序：包括主流程工艺和制冷工艺； 2) Liquefaction separation process: including the main process process and refrigeration process;
a．主流程工艺：将净化含氧煤层气依次通过一级换热器、二级换热器、三级换热器和过冷器换热制冷，并节流后进入精馏塔，在设置在精馏塔塔底的再沸器出口得到液化天然气，精馏塔的塔顶得到氮氧尾气，并利用精馏塔塔顶设置的塔顶冷凝器析出氮氧尾气中含有的少量甲烷组分； a. The main process process: the purified oxygen-containing coalbed methane passes through the primary heat exchanger, secondary heat exchanger, tertiary heat exchanger and subcooler for heat exchange and refrigeration, and enters the rectification tower after throttling. The outlet of the reboiler at the bottom of the distillation tower is used to obtain liquefied natural gas, and the top of the rectification tower is used to obtain nitrogen and oxygen tail gas, and a small amount of methane components contained in the nitrogen and oxygen tail gas are separated out by using the top condenser installed at the top of the rectification tower;
b．制冷工艺：包括混合冷剂工艺和氮冷剂工艺； b. Refrigeration process: including mixed refrigerant process and nitrogen refrigerant process;
b1．混合冷剂工艺：混合冷剂经压缩、冷却后进入重烃分离器分离为气液两相，其中气相混合冷剂依次通过一级换热器和二级换热器降温后，进入位于精馏塔塔底的再沸器加热塔底液体，节流后将气相混合冷剂依次通过三级换热器、二级换热器和一级换热器输出冷量并循环回流至混合冷剂压缩机循环利用；液相混合冷剂通过一级换热器冷却降温、并节流后与回流的气相混合冷剂汇合经一级换热器一起回流至混合冷剂压缩机循环利用； b1 . Mixed refrigerant process: The mixed refrigerant enters the heavy hydrocarbon separator after being compressed and cooled to separate into gas-liquid two-phase, in which the gas-phase mixed refrigerant passes through the primary heat exchanger and the secondary heat exchanger to cool down in turn, and then enters the rectifying The reboiler at the bottom of the tower heats the liquid at the bottom of the tower, and after throttling, the gas-phase mixed refrigerant passes through the third-stage heat exchanger, the second-stage heat exchanger and the first-stage heat exchanger to output cooling capacity and circulates back to the mixed refrigerant for compression. The liquid-phase mixed refrigerant is cooled and lowered by the first-stage heat exchanger, and after throttling, it merges with the returning gas-phase mixed refrigerant and flows back to the mixed refrigerant compressor for recycling through the first-stage heat exchanger;
b2．氮冷剂工艺：氮冷剂经压缩、冷却后依次通过一级换热器、二级换热器、三级换热器和过冷器冷却降温，将经节流后的氮冷剂进入塔顶冷凝器输出冷量，然后将气态的氮冷剂依次通过过冷器、三级换热器、二级换热器、一级换热器逐级升温至常温后回流至氮压缩机循环利用。 b 2 . Nitrogen refrigerant process: After being compressed and cooled, the nitrogen refrigerant passes through the primary heat exchanger, secondary heat exchanger, tertiary heat exchanger and subcooler to cool down in turn, and the throttled nitrogen refrigerant enters the tower The top condenser outputs the cooling capacity, and then the gaseous nitrogen refrigerant passes through the subcooler, the third-stage heat exchanger, the second-stage heat exchanger, and the first-stage heat exchanger to raise the temperature step by step to normal temperature, and then returns to the nitrogen compressor for recycling. .
进一步，经所述压缩净化工序得到的净化含氧煤层气的温度为40℃、绝对压强为0.42MPa。 Furthermore, the temperature of the purified oxygen-containing coalbed methane obtained through the compression and purification process is 40° C. and the absolute pressure is 0.42 MPa.
进一步，所述主流程工艺包括如下步骤： Further, the main flow process includes the following steps:
a1．将净化含氧煤层气依次通过一级换热器、二级换热器、三级换热器和过冷器换热制冷，并经过节流后形成冷凝液和气体的混合物； a 1 . The purified oxygen-containing coalbed methane passes through the primary heat exchanger, secondary heat exchanger, tertiary heat exchanger and subcooler for heat exchange and refrigeration, and forms a mixture of condensate and gas after throttling;
a2．净化含氧煤层气从精馏塔的中部进入精馏塔，冷凝液向下流向塔底，并向上挥发携带的少量氮氧尾气，通过再沸器加热后从冷凝液出口流出，且在冷凝液出口得到温度为-143.5℃、绝对压力为0.32~0.36MPa、甲烷浓度大于等于99%的液化天然气，该液化天然气通过三级换热器换热并达到温度为-155~160℃，压力为0.243MPa的过冷状态后带压存储，得到成品天然气； a 2 . Purified oxygen-containing coalbed methane enters the rectification tower from the middle of the rectification tower, and the condensate flows down to the bottom of the tower, and volatilizes a small amount of nitrogen and oxygen tail gas carried upward, and flows out from the condensate outlet after being heated by the reboiler, and At the outlet, the liquefied natural gas with a temperature of -143.5°C, an absolute pressure of 0.32~0.36MPa, and a methane concentration of 99% or higher is obtained. The liquefied natural gas passes through a three-stage heat exchanger and reaches a temperature of -155~160°C and a pressure of 0.243 MPa supercooled state and then stored under pressure to obtain finished natural gas;
a3．精馏塔的塔顶得到氮氧尾气经塔顶冷凝器析出携带的少量甲烷组分后，再经过冷器复热后进入膨胀机膨胀，膨胀至0.15~0.18MPa后的氮氧尾气依次通过过冷器、三级换热器、二级换热器和一级换热器复热至常温后作为压缩净化工序的再生气。 a 3 . The nitrogen and oxygen tail gas obtained from the top of the rectification tower passes through the top condenser to precipitate a small amount of methane components, and then enters the expander for expansion after being reheated by the cooler. The nitrogen and oxygen tail gas expanded to 0.15~0.18MPa passes through the The cooler, the third-stage heat exchanger, the second-stage heat exchanger and the first-stage heat exchanger are reheated to normal temperature as the regeneration gas for the compression and purification process.
进一步，步骤b1中，混合冷剂的初始压强为0.26MPa，经混合冷剂压缩机压缩至3.2-3.8Mpa，冷却后进入重烃分离器分离为气液两相； Further, in step b1 , the initial pressure of the mixed refrigerant is 0.26MPa, compressed to 3.2-3.8Mpa by the mixed refrigerant compressor, and then enters the heavy hydrocarbon separator after cooling to separate into gas-liquid two-phase;
其中气相混合冷剂依次通过一级换热器和二级换热器降温至-120℃后，进入位于精馏塔塔底的再沸器加热塔底液化天然气，自身被冷却至-148℃，节流后将温度为-160℃的气相混合冷剂依次通过三级换热器、二级换热器和一级换热器输出冷量并循环回流至混合冷剂压缩机循环利用； Among them, the gas-phase mixed refrigerant is cooled to -120°C through the primary heat exchanger and the secondary heat exchanger in turn, and then enters the reboiler at the bottom of the rectification tower to heat the liquefied natural gas at the bottom of the tower, and is itself cooled to -148°C. After throttling, the gas-phase mixed refrigerant with a temperature of -160°C passes through the third-stage heat exchanger, the second-stage heat exchanger and the first-stage heat exchanger to output cooling capacity and circulates back to the mixed refrigerant compressor for recycling;
液相混合冷剂通过一级换热器冷却至-50℃，并节流后与回流的气相混合冷剂汇合经一级换热器一起回流至混合冷剂压缩机循环利用。 The liquid-phase mixed refrigerant is cooled to -50°C through the primary heat exchanger, and after throttling, it merges with the returning gas-phase mixed refrigerant and returns to the mixed refrigerant compressor for recycling through the primary heat exchanger.
进一步，步骤b2中，氮冷剂的初始压强为0.35MPa，经氮压缩机压缩至3.2~3.5MPa，冷却后依次通过一级换热器、二级换热器、三级换热器和过冷器冷却至-172℃，经节流后氮冷剂的温度为-182℃、绝对压强为0.4MPa，进入塔顶冷凝器输出冷量，然后将气态的氮冷剂依次通过过冷器、三级换热器、二级换热器、一级换热器逐级升温至常温后回流至氮压缩机循环利用。 Further, in step b2 , the nitrogen refrigerant has an initial pressure of 0.35MPa, is compressed to 3.2~3.5MPa by a nitrogen compressor, and passes through the primary heat exchanger, secondary heat exchanger, tertiary heat exchanger and The subcooler is cooled to -172°C, the temperature of the nitrogen refrigerant after throttling is -182°C, and the absolute pressure is 0.4MPa, and it enters the top condenser to output cooling capacity, and then the gaseous nitrogen refrigerant passes through the subcooler in turn , The third-stage heat exchanger, the second-stage heat exchanger, and the first-stage heat exchanger gradually increase the temperature to normal temperature and then return to the nitrogen compressor for recycling.
进一步，所述混合冷剂为氮气、甲烷、乙烯、丙烷、异戊烷的混合物。 Further, the mixed refrigerant is a mixture of nitrogen, methane, ethylene, propane, and isopentane.
本发明的有益效果在于： The beneficial effects of the present invention are:
本发明的低浓度煤层气含氧深冷液化制取LNG工艺，通过将制冷工艺分为相对独立的混合冷剂工艺和氮冷剂工艺，并通过混合冷剂工艺控制精馏塔的塔底蒸发量，通过氮冷剂工艺控制精馏塔的塔顶冷凝量，能够独立调整天然气产品的纯度和收率，而且低温区的冷剂仅有氮组分，不存在异丁烷、异戊烷等重组分，从而解决节流不制冷，或冷剂通道堵塞问题。 The low-concentration coalbed methane oxygen-containing cryogenic liquefaction process for producing LNG of the present invention divides the refrigeration process into a relatively independent mixed refrigerant process and nitrogen refrigerant process, and controls the bottom evaporation of the rectification tower through the mixed refrigerant process. The amount of condensation at the top of the rectification tower can be controlled by the nitrogen refrigerant process, which can independently adjust the purity and yield of natural gas products, and the refrigerant in the low temperature zone only has nitrogen components, and there is no isobutane, isopentane, etc. Heavy components, so as to solve the problem of throttling and no refrigeration, or the blockage of refrigerant passages.
通过将精馏塔塔顶得到的氮氧尾气经膨胀机膨胀，膨胀机在常温常压下排空，从而充分回收返流的氮氧气的能量，达到节能减排的目的。 By expanding the nitrogen and oxygen tail gas obtained from the top of the rectification tower through the expander, the expander is evacuated at normal temperature and pressure, so as to fully recover the energy of the nitrogen and oxygen gas that flows back, and achieve the purpose of energy saving and emission reduction.
附图说明 Description of drawings
为了使本发明的目的、技术方案和有益效果更加清楚，本发明提供如下附图进行说明： In order to make the purpose, technical scheme and beneficial effect of the present invention clearer, the present invention provides the following drawings for illustration:
图1为本发明低浓度煤层气含氧深冷液化制取LNG工艺实施例的流程示意图。 Fig. 1 is a schematic flow chart of an embodiment of the process for producing LNG by oxygen-containing cryogenic liquefaction of low-concentration coalbed methane according to the present invention.
具体实施方式 Detailed ways
下面将结合附图，对本发明的优选实施例进行详细的描述。 The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.
首先对适用于本发明低浓度煤层气含氧深冷液化制取LNG工艺的一种制取天然气的装置进行说明。 First, a device for producing natural gas suitable for the process of producing LNG by oxygen-containing cryogenic liquefaction of low-concentration coalbed methane of the present invention will be described.
如图1所示，该低浓度煤层气含氧深冷液化制取天然气的装置，包括主流程系统和制冷系统。 As shown in Figure 1, the low-concentration coalbed methane oxygen-containing cryogenic liquefaction device for producing natural gas includes a main process system and a refrigeration system.
主流程系统沿净化后的煤层气流动方向依次包括一级换热器1、二级换热器2、三级换热器3、过冷器4和精馏塔5，精馏塔5塔顶设置塔顶冷凝器6，精馏塔5塔内设置位于塔底的再沸器7，精馏塔5塔顶设置的氮氧气出口与塔顶冷凝器6的氮氧气出口相连，且精馏塔5的塔底设置冷凝液出口，用于液态天然气流出。过冷器4的煤层气出口与精馏塔5的煤层气入口之间设有节流阀Vf，能够对煤层气进行节流降温。 The main flow system includes the primary heat exchanger 1, the secondary heat exchanger 2, the tertiary heat exchanger 3, the subcooler 4 and the rectification tower 5 along the flow direction of the purified CBM, and the top of the rectification tower 5 is A tower top condenser 6 is set, and a reboiler 7 positioned at the bottom of the tower is arranged in the rectification tower 5 tower, and the nitrogen and oxygen outlet provided at the top of the rectification tower 5 is connected with the nitrogen and oxygen outlet of the tower top condenser 6, and the rectification tower A condensate outlet is provided at the bottom of the tower 5 for liquid natural gas to flow out. A throttling valve Vf is provided between the coalbed gas outlet of the subcooler 4 and the coalbed gas inlet of the rectification tower 5, which can throttle and lower the temperature of the coalbed gas.
制冷系统包括混合冷剂循环系统和氮循环系统。混合冷剂循环系统沿混合冷剂流动方向依次包括混合冷剂压缩机8、混合冷剂冷却器9和重烃分离器10。重烃分离器10的气相混合冷剂出口依次通过一级换热器1和二级换热器2连通于再沸器7的气相混合冷剂入口，再沸器7的气相混合冷剂出口依次通过三级换热器3、二级换热器2和一级换热器1使气相混合冷剂回流并连通于混合冷剂压缩机8的混合冷剂入口，重烃分离器10的液相混合冷剂出口通过一级换热器1后与回流的气相混合冷剂汇合，液相混合冷剂与气相混合冷剂汇合后经一级换热器1一起回流进入混合冷剂压缩机8，使混合冷剂能够循环利用。混合冷剂循环系统还包括节流阀V1，重烃分离器10的液相混合冷剂出口依次通过一级换热器1和节流阀V1与回流的气相混合冷剂汇合，通过设置节流阀V1，能够对液相混合冷剂进行节流减压。再沸器7的气相混合冷剂出口与三级换热器3之间设有节流阀V2，能够对气相混合冷剂进行节流降温。 The refrigeration system includes a mixed refrigerant circulation system and a nitrogen circulation system. The mixed refrigerant circulation system includes a mixed refrigerant compressor 8 , a mixed refrigerant cooler 9 and a heavy hydrocarbon separator 10 in sequence along the mixed refrigerant flow direction. The gas-phase mixed refrigerant outlet of the heavy hydrocarbon separator 10 is connected to the gas-phase mixed refrigerant inlet of the reboiler 7 through the primary heat exchanger 1 and the secondary heat exchanger 2 in sequence, and the gas-phase mixed refrigerant outlet of the reboiler 7 is successively Through the three-stage heat exchanger 3, the secondary heat exchanger 2 and the primary heat exchanger 1, the gas-phase mixed refrigerant is refluxed and communicated with the mixed refrigerant inlet of the mixed refrigerant compressor 8, and the liquid phase of the heavy hydrocarbon separator 10 The outlet of the mixed refrigerant passes through the primary heat exchanger 1 and then merges with the returning gas-phase mixed refrigerant. The liquid-phase mixed refrigerant and the gas-phase mixed refrigerant merge and then flow back together through the primary heat exchanger 1 and enter the mixed refrigerant compressor 8. Make the mixed refrigerant can be recycled. The mixed refrigerant cycle system also includes a throttling valve V 1 , the outlet of the liquid-phase mixed refrigerant of the heavy hydrocarbon separator 10 passes through the primary heat exchanger 1 and the throttle valve V 1 in turn to merge with the returning gas-phase mixed refrigerant. The throttle valve V 1 can throttle and depressurize the liquid-phase mixed refrigerant. A throttling valve V 2 is provided between the gas-phase mixed refrigerant outlet of the reboiler 7 and the three-stage heat exchanger 3 , which can throttle and lower the gas-phase mixed refrigerant.
氮循环系统沿氮冷却剂的流动方向依次包括氮压缩机11和氮冷却器12，氮冷却器12的氮出口依次通过一级换热器1、二级换热器2、三级换热器3和过冷器4连通于塔顶冷凝器6的氮入口，塔顶冷凝器6的氮出口依次通过过冷器4、三级换热器3、二级换热器2和一级换热器1使氮冷却剂回流并连通于氮压缩机11的氮入口，使氮能够循环利用，并对塔顶冷凝器6提供冷量。过冷器4与塔顶冷凝器6的氮入口之间设有节流阀V3，能够对氮冷却剂进行降温。 The nitrogen circulation system sequentially includes a nitrogen compressor 11 and a nitrogen cooler 12 along the flow direction of the nitrogen coolant, and the nitrogen outlet of the nitrogen cooler 12 passes through the primary heat exchanger 1, the secondary heat exchanger 2, and the tertiary heat exchanger in sequence 3 and the subcooler 4 are connected to the nitrogen inlet of the overhead condenser 6, and the nitrogen outlet of the overhead condenser 6 passes through the subcooler 4, the third-stage heat exchanger 3, the second-stage heat exchanger 2 and the first-stage heat exchanger successively. The device 1 refluxes the nitrogen coolant and connects it to the nitrogen inlet of the nitrogen compressor 11 , so that the nitrogen can be recycled and provides cooling capacity to the top condenser 6 . A throttling valve V 3 is provided between the subcooler 4 and the nitrogen inlet of the top condenser 6 to lower the temperature of the nitrogen coolant.
该低浓度煤层气含氧深冷液化制取天然气的装置，通过将制冷系统设置为混合冷剂循环系统和氮循环系统，通过混合冷剂循环系统控制精馏塔5的塔底蒸发量和通过氮循环系统控制精馏塔5的塔顶冷凝量，能够独立调整天然气产品的纯度和收率，而且低温区的冷剂仅有氮组分，不存在异丁烷、异戊烷等重组分，从而解决节流不制冷，或冷剂通道堵塞问题。 The low-concentration coalbed methane oxygen-containing deep-cooling liquefaction device for producing natural gas sets the refrigeration system as a mixed refrigerant circulation system and a nitrogen circulation system, and controls the vaporization at the bottom of the rectification tower 5 through the mixed refrigerant circulation system. The nitrogen circulation system controls the condensation at the top of the rectification tower 5, which can independently adjust the purity and yield of natural gas products, and the refrigerant in the low-temperature zone is only nitrogen components, and there are no heavy components such as isobutane and isopentane. So as to solve the throttling and no refrigeration, or the problem of refrigerant channel blockage.
进一步，主流程系统还包括膨胀机13，精馏塔5的氮氧气出口通过过冷器4连通于膨胀机13的氮氧气入口，膨胀机13的氮氧气出口依次通过过冷器4、三级换热器3、二级换热器2和一级换热器1使氮氧气复热后进入净化工序。通过设置膨胀机13，使其在常温常压下排空，从而充分回收返流的氮氧气的能量，达到节能减排的目的。 Further, the main process system also includes an expander 13, the nitrogen and oxygen outlet of the rectification tower 5 is connected to the nitrogen and oxygen inlet of the expander 13 through the subcooler 4, and the nitrogen and oxygen outlet of the expander 13 passes through the subcooler 4 and the third stage successively. The heat exchanger 3, the secondary heat exchanger 2 and the primary heat exchanger 1 enter the purification process after reheating the nitrogen and oxygen. By setting the expander 13 to make it evacuate under normal temperature and pressure, the energy of the nitrogen and oxygen gas that flows back can be fully recovered, and the purpose of energy saving and emission reduction can be achieved.
进一步，精馏塔5的冷凝液出口通过三级换热器3连通于天然气储罐，使天然气产品达到过冷状态，便于储存。 Furthermore, the condensate outlet of the rectification tower 5 is connected to the natural gas storage tank through the three-stage heat exchanger 3, so that the natural gas product reaches a supercooled state for easy storage.
进一步，混合冷剂冷却器9和氮冷却器12均为水冷却器，能够满足混合冷剂和氮冷却剂的冷却需求，并将其冷却至设定温度。 Further, both the mixed refrigerant cooler 9 and the nitrogen cooler 12 are water coolers, which can meet the cooling requirements of the mixed refrigerant and the nitrogen refrigerant, and cool them to a set temperature.
下面结合上述低浓度煤层气含氧深冷液化制取天然气的装置对本发明低浓度煤层气含氧深冷液化制取LNG工艺的具体实施方式作详细说明。 The specific implementation of the low-concentration coalbed methane oxygen-containing cryogenic liquefaction to produce LNG process of the present invention will be described in detail below in conjunction with the above-mentioned device for producing natural gas through oxygen-containing cryogenic liquefaction of low-concentration coalbed methane.
如图1所示，本实施例的低浓度煤层气含氧深冷液化制取LNG工艺，包括： As shown in Figure 1, the LNG production process of low-concentration coalbed methane oxygen-containing cryogenic liquefaction in this embodiment includes:
1）压缩净化工序：将低浓度含氧煤层原料气经压缩净化后得到净化含氧煤层气，本实施例经压缩净化工序得到的净化含氧煤层气的温度为40℃、绝对压强为0.42MPa。 1) Compression and purification process: The low-concentration oxygen-containing coal bed raw material gas is compressed and purified to obtain purified oxygen-containing coal-bed methane. The temperature of the purified oxygen-containing coal-bed methane obtained through the compression and purification process in this embodiment is 40°C and the absolute pressure is 0.42MPa .
2）液化分离工序：包括主流程工艺和制冷工艺。 2) Liquefaction and separation process: including the main process process and refrigeration process.
a．主流程工艺：将净化含氧煤层气依次通过一级换热器1、二级换热器2、三级换热器3和过冷器4换热制冷，并通过节流阀Vf节流后进入精馏塔5，在设置在精馏塔5塔底的再沸器7出口得到液化天然气，精馏塔5的塔顶得到氮氧尾气，并利用精馏塔塔5顶设置的塔顶冷凝器6析出氮氧尾气中含有的少量甲烷组分。 a. Main process process: the purified oxygen-containing coalbed gas passes through the primary heat exchanger 1, the secondary heat exchanger 2, the tertiary heat exchanger 3 and the subcooler 4 for heat exchange and cooling, and throttling through the throttle valve V f Enter rectifying tower 5 afterward, obtain liquefied natural gas at the outlet of reboiler 7 that is arranged at the bottom of rectifying tower 5 towers, the tower top of rectifying tower 5 obtains nitrogen-oxygen tail gas, and utilizes the tower top that rectifying tower tower 5 top arranges The condenser 6 separates out a small amount of methane components contained in the nitrogen and oxygen tail gas.
b．制冷工艺：包括混合冷剂工艺和氮冷剂工艺。 b. Refrigeration process: including mixed refrigerant process and nitrogen refrigerant process.
b1．混合冷剂工艺：混合冷剂经混合冷剂压缩机8压缩、经混合冷剂冷却器9冷却后进入重烃分离器10分离为气液两相，其中气相混合冷剂依次通过一级换热器1和二级换热器2降温后，进入位于精馏塔5塔底的再沸器7加热塔底液体，经节流阀V2节流后将气相混合冷剂依次通过三级换热器3、二级换热器2和一级换热器1输出冷量并循环回流至混合冷剂压缩机8循环利用；液相混合冷剂通过一级换热器1冷却降温、并通过节流阀V1节流后与回流的气相混合冷剂汇合经一级换热器1一起回流至混合冷剂压缩机8循环利用。 b1 . Mixed refrigerant process: The mixed refrigerant is compressed by the mixed refrigerant compressor 8, cooled by the mixed refrigerant cooler 9, and then enters the heavy hydrocarbon separator 10 to be separated into gas-liquid two-phase, in which the gas-phase mixed refrigerant passes through the first-stage heat exchange in sequence After cooling down in the heat exchanger 1 and the secondary heat exchanger 2, it enters the reboiler 7 located at the bottom of the rectification tower 5 to heat the liquid at the bottom of the tower, and after throttling through the throttle valve V 2 , the gas-phase mixed refrigerant passes through the three-stage heat exchange successively 3, the secondary heat exchanger 2 and the primary heat exchanger 1 output cooling capacity and circulate back to the mixed refrigerant compressor 8 for recycling; the liquid-phase mixed refrigerant is cooled by the primary heat exchanger 1, and passed through the After throttling, the flow valve V 1 merges with the returning gas-phase mixed refrigerant, passes through the primary heat exchanger 1, and flows back to the mixed refrigerant compressor 8 for recycling.
本实施例的混合冷剂工艺的工艺参数如下： The processing parameters of the mixed refrigerant process of the present embodiment are as follows:
本实施例的混合冷剂的初始压强为0.26MPa，经混合冷剂压缩机8压缩至3.2-3.8Mpa，冷却后进入重烃分离器10分离为气液两相；其中气相混合冷剂依次通过一级换热器1和二级换热器2降温至-120℃后，进入位于精馏塔5塔底的再沸器7加热塔底液化天然气，自身被冷却至-148℃，节流后将温度为-160℃的气相混合冷剂依次通过三级换热器3、二级换热器2和一级换热器1输出冷量并循环回流至混合冷剂压缩机8循环利用；液相混合冷剂通过一级换热器1冷却至-50℃，并节流后与回流的气相混合冷剂汇合经一级换热器1一起回流至混合冷剂压缩机8循环利用，能够满足液化天然气的制取要求，并控制精馏塔5的塔底蒸发量。 The initial pressure of the mixed refrigerant in this embodiment is 0.26MPa, and it is compressed to 3.2-3.8Mpa by the mixed refrigerant compressor 8, and after cooling, it enters the heavy hydrocarbon separator 10 and is separated into gas-liquid two-phase; wherein the gas-phase mixed refrigerant passes through After the primary heat exchanger 1 and the secondary heat exchanger 2 cool down to -120°C, they enter the reboiler 7 located at the bottom of the rectification tower 5 to heat the liquefied natural gas at the bottom of the tower, and the liquefied natural gas at the bottom of the tower is cooled to -148°C. The gas-phase mixed refrigerant with a temperature of -160°C passes through the third-stage heat exchanger 3, the second-stage heat exchanger 2 and the first-stage heat exchanger 1 to output cooling capacity and circulates back to the mixed refrigerant compressor 8 for recycling; the liquid The phase mixed refrigerant is cooled to -50°C through the primary heat exchanger 1, and after throttling, it merges with the returning gas phase mixed refrigerant and flows back to the mixed refrigerant compressor 8 through the primary heat exchanger 1 for recycling, which can meet the The production requirements of liquefied natural gas, and control the bottom evaporation of rectification tower 5.
b2．氮冷剂工艺：氮冷剂经氮压缩机11压缩、经氮冷却器12冷却后依次通过一级换热器1、二级换热器2、三级换热器3和过冷器4冷却降温，将经节流阀V3节流后的氮冷剂进入塔顶冷凝器6输出冷量，然后将气态的氮冷剂依次通过过冷器4、三级换热器3、二级换热器2、一级换热器1逐级升温至常温后回流至氮压缩机11循环利用。 b 2 . Nitrogen refrigerant process: nitrogen refrigerant is compressed by nitrogen compressor 11, cooled by nitrogen cooler 12, and then cooled by primary heat exchanger 1, secondary heat exchanger 2, tertiary heat exchanger 3 and subcooler 4 To lower the temperature, the nitrogen refrigerant throttled by the throttle valve V3 enters the top condenser 6 to output cooling capacity, and then the gaseous nitrogen refrigerant passes through the subcooler 4, the third-stage heat exchanger 3, and the second-stage heat exchanger in sequence. Heater 2 and primary heat exchanger 1 are heated up to normal temperature step by step and then flow back to nitrogen compressor 11 for recycling.
本实施例的氮冷剂工艺的工艺参数如下： The process parameters of the nitrogen refrigerant process of the present embodiment are as follows:
本实施例的氮冷剂的初始压强为0.35MPa，经氮压缩机11压缩至3.2~3.5MPa，冷却后依次通过一级换热器1、二级换热器2、三级换热器3和过冷器4冷却至-172℃，经节流后氮冷剂的温度为-182℃、绝对压强为0.4MPa，进入塔顶冷凝器6输出冷量，然后将气态的氮冷剂依次通过过冷器4、三级换热器3、二级换热器2、一级换热器1逐级升温至常温后回流至氮压缩机11循环利用，能够满足液化天然气的制取要求，并控制精馏塔5的塔顶冷凝量。 The nitrogen refrigerant in this embodiment has an initial pressure of 0.35 MPa, is compressed to 3.2~3.5 MPa by the nitrogen compressor 11, and passes through the primary heat exchanger 1, the secondary heat exchanger 2, and the tertiary heat exchanger 3 in turn after cooling. And subcooler 4 is cooled to -172°C, the temperature of the nitrogen refrigerant after throttling is -182°C, and the absolute pressure is 0.4MPa, it enters the tower top condenser 6 to output cooling capacity, and then the gaseous nitrogen refrigerant passes through The supercooler 4, the third-stage heat exchanger 3, the second-stage heat exchanger 2, and the first-stage heat exchanger 1 are heated step by step to normal temperature and then returned to the nitrogen compressor 11 for recycling, which can meet the production requirements of liquefied natural gas, and The amount of condensation at the top of the distillation column 5 is controlled.
本实施例的低浓度煤层气含氧深冷液化制取LNG工艺，通过将制冷工艺分为相对独立的混合冷剂工艺和氮冷剂工艺，并通过混合冷剂工艺控制精馏塔的塔底蒸发量，通过氮冷剂工艺控制精馏塔的塔顶冷凝量，能够独立调整天然气产品的纯度和收率，而且低温区的冷剂仅有氮组分，不存在异丁烷、异戊烷等重组分，从而解决节流不制冷，或冷剂通道堵塞问题。 The LNG production process of low-concentration coalbed methane cryogenic liquefaction with oxygen in this embodiment divides the refrigeration process into relatively independent mixed refrigerant process and nitrogen refrigerant process, and controls the bottom of the rectification tower through the mixed refrigerant process Evaporation, through the nitrogen refrigerant process to control the condensation at the top of the rectification tower, the purity and yield of natural gas products can be adjusted independently, and the refrigerant in the low temperature zone only has nitrogen components, and there is no isobutane and isopentane Equal weight components, so as to solve the problem of throttling and no refrigeration, or refrigerant passage blockage.
进一步，本实施例的主流程工艺具体包括如下步骤： Further, the main flow process of this embodiment specifically includes the following steps:
a1．将净化含氧煤层气依次通过一级换热器1、二级换热器2、三级换热器3和过冷器4换热制冷，并经过节流阀Vf节流后形成冷凝液和气体的混合物； a 1 . The purified oxygen-containing coalbed gas passes through the primary heat exchanger 1, the secondary heat exchanger 2, the tertiary heat exchanger 3 and the subcooler 4 for heat exchange and refrigeration, and forms condensate after throttling through the throttle valve V f and gas mixtures;
a2．净化含氧煤层气从精馏塔5的中部进入精馏塔5，冷凝液向下流向塔底，并向上挥发携带的少量氮氧尾气，通过再沸器7加热后从冷凝液出口流出，且在冷凝液出口得到温度为-143.5℃、绝对压力为0.32~0.36MPa、甲烷浓度大于等于99%的液化天然气，该液化天然气通过三级换热器3换热并达到温度为-155~160℃，压力为0.243MPa的过冷状态后带压存储，得到成品天然气； a 2 . The purified oxygen-containing coal bed gas enters the rectification tower 5 from the middle of the rectification tower 5, and the condensate flows downward to the bottom of the tower, and volatilizes a small amount of nitrogen and oxygen tail gas carried upward, and flows out from the condensate outlet after being heated by the reboiler 7, and At the outlet of the condensate, liquefied natural gas with a temperature of -143.5°C, an absolute pressure of 0.32~0.36MPa, and a methane concentration greater than or equal to 99% is obtained. The liquefied natural gas passes through the three-stage heat exchanger 3 to exchange heat and reaches a temperature of -155~160°C , the pressure is 0.243MPa in a supercooled state and then stored under pressure to obtain finished natural gas;
a3．精馏塔5的塔顶得到氮氧尾气经塔顶冷凝器6析出携带的少量甲烷组分后，再经过冷器4复热后进入膨胀机13膨胀，膨胀至0.15~0.18MPa后的氮氧尾气依次通过过冷器4、三级换热器3、二级换热器2和一级换热器1复热至常温后作为压缩净化工序的再生气。 a 3 . The nitrogen and oxygen tail gas obtained from the top of the rectification tower 5 passes through the tower top condenser 6 to precipitate a small amount of methane components, and then enters the expander 13 for expansion after being reheated by the cooler 4, and the nitrogen and oxygen after expanding to 0.15~0.18MPa The tail gas is reheated to normal temperature through the subcooler 4, the third-stage heat exchanger 3, the second-stage heat exchanger 2, and the first-stage heat exchanger 1 in sequence, and then used as regeneration gas for the compression and purification process.
通过将精馏塔5塔顶得到的氮氧尾气经膨胀机13膨胀，膨胀机13在常温常压下排空，从而充分回收返流的氮氧气的能量，达到节能减排的目的。 By expanding the nitrogen and oxygen tail gas obtained at the top of the rectification tower 5 through the expander 13, the expander 13 is evacuated under normal temperature and pressure, so as to fully recover the energy of the nitrogen and oxygen backflow, and achieve the purpose of energy saving and emission reduction.
进一步，本实施例的混合冷剂为氮气、甲烷、乙烯、丙烷、异戊烷的混合物，能够满足在液化天然气制取的各个环节中的温度控制要求，混合冷剂中各个组分的配比根据实际制冷量的需求进行设定，当然，混合冷剂还可采用现有的其他组分的混合冷剂，不再累述。 Further, the mixed refrigerant in this embodiment is a mixture of nitrogen, methane, ethylene, propane, and isopentane, which can meet the temperature control requirements in each link of liquefied natural gas production, and the proportion of each component in the mixed refrigerant It is set according to the demand of the actual cooling capacity. Of course, the mixed refrigerant can also use the existing mixed refrigerant of other components, which will not be repeated here.
最后说明的是，以上优选实施例仅用以说明本发明的技术方案而非限制，尽管通过上述优选实施例已经对本发明进行了详细的描述，但本领域技术人员应当理解，可以在形式上和细节上对其作出各种各样的改变，而不偏离本发明权利要求书所限定的范围。 Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail through the above preferred embodiments, those skilled in the art should understand that it can be described in terms of form and Various changes may be made in the details without departing from the scope of the invention defined by the claims.
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| CN116987536A (en) * | 2023-06-15 | 2023-11-03 | 英德市西洲气体有限公司 | Argon removal process for methane tower |
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